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Sometimes, new septic systems can be like square pegs in round holes.
By Amy Sorkin Kurland
Such was the case at a rental cottage on Keuka Lake, just outside Penn Yan, NY. The hoopla started when the owner of a rental cottage wanted to sell the property.
Whenever there’s a property transfer in the Keuka Lake watershed district, there’s an inspection of the existing septic systems. When the inspections and tests were done on this particular cottage, the system was determined to be undersized. Although it had not failed yet, it was heading on that path. “It would’ve failed in about a year,” says Roger Ribble of Ribble Septic Service, the septic contractor on this project, “because the biomatting was already up into the top of the leach pit.”
The site, however, presented some challenges that prohibited the use of a conventional system. To come up with a solution, the owner hired the Keuka Watershed Improvement Cooperative (KWIC), an organization formed in 1993 to protect and improve the purity of the waters in and around the Keuka Lake watershed.
Challenging Grounds
According to New York State health codes, not only was the existing system not big enough for the property, but it also didn’t fall within the requirements of the area’s septic system location. “If you went past the set back distance, you were on a slope,” explains Dick Osgood, project engineer, who was the designer of the new system. “The slope exceeded the standards, and putting a system closer to the lake didn’t work under the state’s standards either.”
To work within the limited area available between the cottage and the lake, Osgood decided to create a retaining wall. The strategy was that the retaining wall would allow the contractors to build a footprint that could accept the sanitary waste while falling within New York state code regulations. “This footprint was still limited due to the proximity of the house, so we had to minimize the amount of leach lines we provided,” says Osgood.
To accomplish this task, Osgood chose to combine the use of two wastewater treatment products, the Pirana Sludgehammer, by Pirana ABG Inc., and the Eljen GSF geotextile sand filter. In short, the Pirana allowed for enhanced waste treatment within a confined area, and the Eljen allowed for minimization of the leach lines.
The Great Wall of Keuka
Behind the cottage there was a steep, 45-degree slope leading to the lake shoreline. New York state code did not allow leach lines to be installed on slopes that were more than 15 degrees. The retaining wall was created to soften the 45-degree slope.
The lake shoreline was approximately 100 feet from the retaining wall. There was also an intermittent stream approximately 50 feet away. To be far enough away from the lake and the stream, the leach lines had to be placed as close as possible to the home. Because of the high quality of the effluent coming from the Pirana unit, the Health Department allowed this new septic system to be placed closer to these bodies of water than normally permitted.
The dry well the property had previously been using was abandoned, but the old septic tank was retained for the new design. The first step in the installation was putting in the Pirana unit, which took about 4 hours. This was by far the easiest aspect of the job. By the time rental season was over and the contractors were able to attain the necessary board of health approvals, it had been about eight months since the Pirana was installed. At this point the contractors could finally began the next step: construction of the wall.
The wall and the system design had to be pre-engineered by Osgood and then submitted to the New York State Board of Health Department for a permit. The retaining wall was built according to Osgood’s specifications, at approximately 12 feet high and 100 feet long. It was made out of 235 tons of gabion rock, with gabion baskets.
“It took about 2½ weeks to build the wall and do the tamping behind it,” begins Ribble. “Every couple of layers we had to do a perk test so we knew we had consistency all the way through. Those would take about 17 minutes average. We were creating natural soil by compacting it, so we were looking for 15-20–minute perk in this case.”
First the old systems had to be relocated, pumped, and cleaned out. Then the contractors had to set up new drop boxes for the three laterals that would incorporate the Eljen unit. “The Eljen laterals were in a very tightened, restrained area,” says Ribble. “The three of them were about 4 feet wide and about 48 feet long. What we did was place about 7 inches of sand for a base, on which the Eljen sits. Then we ran the distribution pipes, which are a perforated plastic, right on top of the Eljen unit, dead center. These Eljen units have clipping pins that slip over the top of the pipes to hold them in place.”
Once the distribution pipes were in place, a geotextile fabric was placed on top of the Eljen unit to protect it from dirt and sand. Then more sand was put on top and on the side. “Then you rebed it in sand,” adds Ribble. “And you’re ready to back fill.”
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| To comply with state code, a carefully constructed retaining wall was designed
to soften the 45-degree slope. |
D’Ya Wanna Pirana?
In a nutshell, the Pirana Sludgehammer (the latest version of what was originally known only as the Pirana) changes an anaerobic treatment system to an aerobic one. “What this system does is turn your septic system into a mini treatment plant,” explains Osgood. “You can put these in without digging up a lot of area. We put the unit in and inoculated it with the Pirana blend, which is a special blend of bacteria. We were still using the old system while we added this to clarify the water and bring it up to standard.”
Pirana ABG Inc. originally created the Pirana to grow a particular group of bacteria. “We wanted to begin using these bacteria in wastewater, but the wastewater bacteria are aerobic bacteria,” says Dan Wickham, president of Pirana ABG Inc. and co-inventor of the Pirana. “These bacteria are effective aerobically, but they can live for a certain amount of time anaerobically.”
Wickham knew that if they could figure out a way to make these bacteria survive in a septic system, the bacteria could be very effective in unclogging leach lines. Eventually he and his co-inventor figured out how to take advantage of air in such a way as to create the environment in a tank in which the bacteria could live. “The environment we created with the Pirana Sludgehammer, an aerobic bacteria generator, allowed us to control and introduce the particular bacteria we wanted.”
The Sludgehammer is a column about 3 feet tall and 1 foot in diameter. Air is introduced into the column, which sits on the bottom of the septic tank. There’s an air pump that sits by the house, removed from the tank. Air is run through the pump from the house to the Sludgehammer.
“The Sludgehammer consumes everything in the tank,” says Wickham. “And it converts it all to bacteria. We end up with water that’s equivalent to that produced by a municipal wastewater treatment plant. Although our original intent for the Pirana was to recover failed leach lines by cleaning up and preventing clogging, we discovered over time that it provided highly effective wastewater treatment as well.”
The Sludgehammer allows for two major benefits. First, because the water is so highly treated, it can be reclaimed with a subsurface drip system. Second, when combined with the Eljen system, the Sludgehammer allows a house on a small lot to get good treatment. Such was the case with the Keuka guest
cottage.
A Powerful Duo
The Eljen GSF geotextile sand filter module consists of two parts: a geotextile filtration component, which is a corrugated surface, and a cuspated plastic core, which provides a support surface for the geotextile fabric.
The geotextile filtration unit stores the wastewater for treatment and also supports aerobic digestion. The geotextile fabric, a course cloth, constrains the flow of the wastewater out, encouraging nitrification in the sand layer that receives the effluent prior to the soil. This supports nitrification of the wastewater. “The end result is higher-quality effluent permeating the soil. Less oxygen is needed in the soil, reducing the potential clogging by mucogenic bacteria, which control the rate of infiltration and the infiltration area needed. Bottom line is that more effluent can be absorbed in a smaller area,” says Stephen Dix, P.E. and president of Septic Solutions LLC, who does R&D for Eljen Corp.
“The Eljen system is very user-friendly. It’s a pre-manufactured unit you place on prepared ground, put your distributor pipe onto, anchor it in place, and you’re pretty well done,” says Osgood.
In addition to using the Eljen GSF product in its entirety at the site (in conjunction with the Sludgehammer), a component of the Eljen was also used to enhance the Sludgehammer’s performance. The Eljen includes a cuspated plastic core that has a thickness of ¾ inch from either side. It was rolled continuously and placed in the Pirana to serve as a fixed-film bacteria collector for digestion purposes.
In the inside of the Pirana, at the bottom, is a microfine bubble diffuser. As the air leaves the diffuser it rises through a central pipe and the cuspated media (which is wrapped around this pipe) and draws water in at the base. The water circulates at an estimated rate of 20,000 gallons per day.
“The plastic core is just a surface area,” begins Dix.“ It’s an attached growth reactor. The core holds on to air, along with bacteria. It also captures a lot of solids. What we’re looking for is a product with a high surface area to maximize the amount of bacteria to grow on the system.”
The cuspated plastic media provides a fairly open surface area, which is conducive to the survival and growth of the intentional bacteria community. The Pirana and the Eljen together are more stable, resilient, and robust than an extended aeration process. They also require less energy to operate.
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| Geotextile sand filtration units can store wastewater for treatment and can support aerobic digestion. |
“When you combine the Sludgehammer with the Eljen, you get both treatment in the tank [the Pirana] and protection on the soil [the Eljen]. So you have a very effective system that has a redundancy,” says Wickham. The rental cottage, incidentally, is one of the earlier uses of this particular Sludgehammer/Eljen combination, even though thousands of both systems have been put in independently.
Pirana ABG Inc. first discovered this combination when it was repairing some septic installations that had been poorly done. The soil around this particular Eljen system had failed, so Pirana was brought in to recover it. “The Eljen system by itself is very hard to fail,” says Wickham, “so this was an extreme situation where the restaurant was outputting fat, grease, and disinfectants very heavily. But when we did come in, we realized that we could take advantage of the Eljen to use a much smaller footprint on the property, and then use the Pirana to add an extra level of protection from clogging.”
As it turned out, this system was way beyond what was necessary at the cottage.
Unusual Circumstances, Outstanding Results
“It seemed like everywhere we turned there was a code restriction,” says Ribble. “The slope was too steep, the treatment area was too close to the lake, and the treatment area was too close to the house.” Because of state limitations on how close you can get to the water table, which in this case was both the lake and a stream, the area left on which to build the wall was quite small.
As mentioned before, the retaining wall solved the slope issue. “Because the quality of the effluent that comes from the Pirana is so good, and because the Eljen core decreased the leach lines, eventually the state allowed us to install the systems in the small area that would otherwise be restricted due to code,” says Ribble.
Although there were a lot of obstacles to overcome to install the new system, it also proved to have benefits not seen with conventional systems. For Osgood, what made this project particularly unique was the decreased lineal foot of the leach lines (by the State’s standards) due to the increased treatment provided by the efficiency of the Eljen and Pirana systems.
Ribble was particularly impressed with the lack of biomat. “This design took a conventional septic system and marginal secondary treatment system, which was just a dry well in this case, and allowed the effluent to change so dramatically that the biomat around the dry well was or is being eradicated.”
Installation And Beyond
In addition to the code challenges—which required a lot of communication with the state on the part of Osgood and Ribble before solutions were agreed on—there was no room on the sides of the cottage to bring in materials. “Everything had to be picked up and put on the job,” explains Ribble. “One neighbor gave us no access, and everything else had to be picked up from the bottom and placed over the wall. Everything was brought in with trucks and raised with a machine over the top of the wall. The mouth of where we had to come in would not allow for a bigger truck, so we had to use smaller trucks, which of course took more time. We also had two fences to get around. This kind of delivery added a lot of cost to the job, but there just wasn’t another way to do it.”
To add to the burden, it was rainy season, so a few days were lost as well. But Ribble and his team patiently plowed on, and the entire installation took about 3½ weeks total.
“The Pirana and the Eljen are typically not difficult to install. But because of the retaining wall and everything that came with it, when we installed it on this site, I’d say it was a an 8 or 9 in difficulty,” says Ribble. He says the most challenging aspect was installing the wall and the fill behind it. “The wall is gabion rock, and the owner wanted it to look more aesthetically appealing. So we took more time to do a nicer job of placing the rocks inside the baskets.”
Pirana has a service contract. Ribble goes out a couple of times a year to service it, and once a year his team rejuvenates the system by adding more bacteria. The Eljen, on the other hand, doesn’t need servicing. An owner needs only to maintain his septic tank to secure the quality of the Eljen, which comes with a 10-year warranty if it’s put in by a certified, trained installer.
Installation was completed in spring of 2006. So far the system has been working beautifully. “I haven’t had a phone call yet,” says Ribble. “And to my knowledge, the engineer hasn’t either. In fact, we just did a service call on it two months ago and it was working perfectly.”
Journalist Amy Sorkin Kurland specializes in marketing communications
OW - January/February 2007 |
